Final answer:
Specimen integrity during microscopic examination is crucial, and includes documenting size with a scale, preserving labels, and proper fixation. Fixation techniques vary based on specimen type, with chemical fixation for delicate samples and heat fixation for more robust samples. Staining methods and dyes highlight different features and allow for differentiation between cell types.
Step-by-step explanation:
When handling specimens for microscopic examination, certain procedures, if done incorrectly or incomplete, can lead to the specimen being useless, which might necessitate redrawing the specimen at a later time. A few key aspects need attention to ensure the integrity of the specimen. Firstly, including a scale, like a coin or ruler, in the photograph of the specimen helps to remember its size, which is fundamental for accurate documentation. Additionally, specimens might have labels or unique identifiers that should not be moved, as they are essential for tracking and preventing confusion in the lab.
Fixing a specimen is important before viewing it under a light microscope because it preserves the specimen in a life-like state, allowing for accurate study and preventing decay. Chemical fixation is typically reserved for delicate specimens that might be distorted or ruptured by heat, whereas heat fixation is often used for bacterial samples to adhere them to the slide. Acidic dyes may react differently from basic dyes due to the pH sensitivity of certain cellular components, influencing staining patterns. Moreover, a positive stain colors the specimen itself, facilitating its visibility, while a negative stain dyes the background, creating a silhouette of the organism.
Finally, the difference between simple staining and differential staining lies in the complexity; simple staining uses a single dye to make all cells visible, whereas differential staining uses multiple dyes to differentiate between cell types or structures, such as in Gram staining.